Ambassador getting Anne worried about British narcotic (7)

I believe the answer is:

henbane

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'narcotic' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.

'ambassador getting anne worried about british' is the wordplay.
'ambassador' becomes 'he' (His or Her Excellency).
'getting' says to put letters next to each other.
'worried' indicates an anagram.
'about' is an insertion indicator.
'british' becomes 'b' (abbreviation e.g. in 'BBC').
'anne' anagrammed gives 'nane'.
'nane' placed around 'b' is 'nbane'.
'he'+'nbane'='HENBANE'

Can you help me to learn more?

(Other definitions for henbane that I've seen before include "poison" , "Poisonous plant" , "Poisoner" .)

I've seen this clue in The Daily Express.

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